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Microchip Technology MCP795W22T-I/ST
- Part No.:
- MCP795W22T-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Real Time Clocks
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
MCP795W22T-I/ST.pdf
- Description:
- IC RTC CLK/CALENDAR SPI 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,046
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Product details
Overview
MCP795W22T-I/ST from Microchip Technology is a battery-backed SPI Real-Time Clock/Calendar (RTCC) IC with integrated 2 Kbit EEPROM, EUI-64™ MAC address, programmable watchdog timer, dual event detect modules, and digital trimming. It maintains time to hundredth-of-second resolution across -40°C to +85°C, logs power-fail/power-up timestamps, and operates from 1.8V–3.6V main supply or 1.3V–3.6V backup. Used in industrial metering, medical devices, and networked edge sensors requiring traceable time-stamping.
For engineers reviewing the MCP795W22T-I/ST datasheet, MCP795W22T-I/ST pinout, MCP795W22T-I/ST application, or MCP795W22T-I/ST equivalent, key selection criteria include ±1 ppm digital trim range, 1.0 µA VBAT timekeeping current, dual alarm assignment to IRQ/WDO pins, 128-bit protected EEPROM for secure node ID storage, and compatibility with 6–9 pF 32.768 kHz crystals.
Technical Context
The MCP795W22T-I/ST implements a fully autonomous RTCC using an internal 32.768 kHz oscillator circuit optimized for external crystals with 6–9 pF load capacitance. Its on-chip digital trimming provides ±259 ppm adjustment range at ±1 ppm resolution, enabling precise calibration over temperature and aging.
It features two independent interrupt-capable peripherals: a high-speed event detect module supporting programmable pulse counting, and a low-speed module with configurable debounce timing for mechanical switch inputs. Both can trigger IRQ or WDO outputs, and alarms may be routed to either pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Time Resolution | Hundredth-of-second granularity with leap-year compensation through year 2399 |
| Oscillator Accuracy | ±1 ppm digital trim resolution; ±259 ppm total trim range for crystal tolerance compensation |
| Timekeeping Current | 1.0 µA typical from VBAT at 3.0V - enables >10-year coin-cell operation |
| Backup Voltage Range | 1.3V to 3.6V - supports common lithium and silver-oxide backup cells |
| SPI Interface Speed | Up to 5 MHz at VCC ≥ 2.5V - ensures fast register access in real-time systems |
| Memory Resources | 64-byte SRAM, 2 Kbit EEPROM (page write ≤8 bytes), and 128-bit protected EEPROM preprogrammed with EUI-64™ |
| Power-Fail Timestamp | Logs exact time of VCC loss and restoration in dedicated registers - critical for forensic logging |
Pinout & Package
14-pin SOIC (3.9 mm × 8.7 mm) and TSSOP (4.4 mm × 5.0 mm) packages; both share identical pin mapping and thermal performance per DS20002280E.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| X1 | Crystal input / external clock input | Accepts 32.768 kHz crystal or buffered clock; enables EXTOSC mode when configured |
| X2 | Crystal output | Drives crystal resonator; must be left floating if external clock used |
| VBAT | Backup supply input | Automatically powers RTCC and SRAM during VCC dropout; switchover at 1.3–1.7V |
| WDO | Watchdog timer output | Open-drain; asserts low pulse on WDT timeout or assigned alarm - requires 10 kΩ pull-up |
| IRQ | Interrupt output | Open-drain; signals event detection or assigned alarm - supports VCC or VBAT pull-up |
| CS | Chip select input | Active-low SPI enable; initiates instruction decode on high-to-low transition after power-up |
| VSS | Ground reference | Primary return path for all digital and analog circuits; must be low-impedance |
| SO | Serial data output | Tri-state output updated after SCK falling edge; high-impedance when CS high |
| SI | Serial data input | Latches data on SCK rising edge; accepts instruction, address, and payload bytes |
| SCK | Serial clock input | Synchronizes all SPI transfers; max 5 MHz at VCC ≥ 2.5V |
| EVHS | High-speed event input | Detects up to 1 MHz pulses; triggers IRQ after programmable count - no external debouncing needed |
| EVLS | Low-speed event input | Configurable debounce period (1–255 ms); ideal for pushbutton or reed-switch interfaces |
| CLKOUT | Square wave output | Programmable frequency output (32.768 kHz, 1 kHz, 64 Hz, 1 Hz) - usable as system clock source |
| VCC | Main power supply | 1.8V–3.6V operation; powers EEPROM writes, SPI interface, and active RTCC functions |
Key Features
| Feature | Design Value |
|---|---|
| Dual programmable alarms | Independent alarm 0 and alarm 1 with maskable fields down to hundredth-of-second; assignable to IRQ or WDO |
| Power-fail timestamping | Records exact time of VCC loss and restoration in dedicated 8-register blocks - enables root-cause analysis |
| EUI-64™ node address | Factory-programmed 64-bit IEEE identifier stored in protected EEPROM - eliminates host-side MAC generation |
| On-chip digital trimming | ±259 ppm adjustment range at ±1 ppm steps - compensates crystal tolerance without external components |
| Event detect modules | Separate high-speed (pulse counting) and low-speed (debounce) inputs - reduces MCU firmware overhead |
| Battery-backed SRAM | 64 bytes retained during VCC dropout - preserves runtime configuration without external backup circuitry |
Applications
| Smart Energy Metering | Industrial PLC HMI |
|---|---|
Use Scenario: Time-stamped energy consumption logging with tamper detection and firmware update validation. IC Role / Device Role / Timing Role: Primary RTCC providing synchronized timestamping for kWh measurements and secure boot verification. Use Value: Power-fail timestamp captures exact outage onset; EUI-64™ enables unique device identity for secure OTA updates. | Use Scenario: Operator interface with button-driven navigation, real-time diagnostics, and scheduled maintenance alerts. IC Role / Device Role / Timing Role: System timekeeper and event coordinator managing button debounce, alarm scheduling, and display refresh timing. Use Value: EVLS pin handles mechanical switch bounce; dual alarms trigger maintenance windows without CPU polling. |
| Medical Wearable Sensor | Networked Building Controller |
Use Scenario: Continuous physiological monitoring with battery life optimization and clinical-grade time correlation. IC Role / Device Role / Timing Role: Low-power time source maintaining accurate timestamps across sleep/wake cycles and battery swaps. Use Value: 1.0 µA VBAT current extends CR2032 life beyond 10 years; hundredth-of-second resolution aligns sensor samples to UTC. | Use Scenario: HVAC zone control with occupancy sensing, schedule-based actuation, and energy reporting. IC Role / Device Role / Timing Role: Central time authority synchronizing thermostat schedules, sensor sampling, and BACnet time-of-day messages. Use Value: CLKOUT provides 1 Hz signal for microcontroller wake-up; 2 Kbit EEPROM stores seasonal setpoints persistently. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar RTC/calendar applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP795W21T-I/ST | Same package and pinout; includes EUI-48™ instead of EUI-64™; 2 Kbit EEPROM unchanged | Preferred where legacy 48-bit MAC addressing is required (e.g., IPv4-only networks) | Select when EUI-48™ suffices and EUI-64™ is unnecessary |
| DS3231M+ | Integrated TCXO (±2 ppm); higher accuracy but no event detect modules or protected EEPROM | Used where absolute time accuracy outweighs feature richness (e.g., precision instrumentation) | Choose only if ±2 ppm stability is mandatory and event detection/EUI-64™ are not needed |
Compared with MCP795W21T-I/ST and DS3231M+, the MCP795W22T-I/ST uniquely combines EUI-64™ node identity, dual event detection, and programmable alarm routing - making it optimal for secure, event-driven embedded systems requiring long-term battery-backed timekeeping.
Availability
MCP795W22T-I/ST is available at Aetrix Electronics and suitable for industrial metering, medical wearables, and building automation systems requiring stable component supply, long-life backup operation, and secure device identity.
Supply support for MCP795W22T-I/ST includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and timing solutions for industrial, automotive, and consumer markets.
The MCP795Wxx product line delivers highly integrated, battery-backed RTCs with enhanced system-level features - designed specifically for resource-constrained embedded applications needing reliable timekeeping, event handling, and secure identity storage.
FAQ
What is the primary function of the MCP795W22T-I/ST?
The MCP795W22T-I/ST is a battery-backed SPI Real-Time Clock/Calendar IC that maintains accurate time and date (including hundredth-of-second resolution and leap-year compensation through 2399), logs power-fail/power-up events, and provides 2 Kbit EEPROM with factory-programmed EUI-64™. It serves as a self-contained timing and identity solution for embedded systems where reliability and low power are critical.
How does the MCP795W22T-I/ST handle crystal oscillator calibration?
The MCP795W22T-I/ST uses on-chip digital trimming with ±1 ppm resolution and ±259 ppm total range to compensate for crystal tolerance and temperature drift. Calibration values are written to the OSCTRIM register (address 0x09) and applied automatically by the internal oscillator circuit - no external components or manual adjustments are required.
Can the MCP795W22T-I/ST operate without an external crystal?
Yes - the MCP795W22T-I/ST supports external clock input mode via the X1 pin. When the EXTOSC bit in the CONTROL register is set, the device disables its internal crystal oscillator and accepts a 32.768 kHz square-wave clock directly. In this configuration, X2 must be left floating, and crystal load capacitors are omitted.
What is the purpose of the EVHS and EVLS pins on the MCP795W22T-I/ST?
The EVHS (high-speed event detect) and EVLS (low-speed event detect) pins provide hardware-accelerated input processing: EVHS detects fast pulses (up to ~1 MHz) and triggers IRQ after a programmable count; EVLS applies configurable debounce (1–255 ms) to mechanical inputs like buttons or switches. Both reduce MCU firmware burden and improve system responsiveness.
Does the MCP795W22T-I/ST support multiple alarm outputs?
Yes - the MCP795W22T-I/ST includes two independent alarms (ALM0 and ALM1), each configurable to match time/date fields down to hundredth-of-second. Alarm outputs can be routed to either the IRQ or WDO pin via control register bits, enabling flexible interrupt handling without additional logic or GPIO allocation.
MCP795W22T-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, EEPROM, Leap Year, Square Wave Output, SRAM, Unique ID, Watchdog Timer
- Memory Size:
- 64B
- Time Format:
- HH:MM:SS:hh (12/24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- SPI
- Voltage - Supply:
- 1.8V ~ 3.6V
- Voltage - Supply, Battery:
- 1.3V ~ 3.6V
- Current - Timekeeping (Max):
- 1µA @ 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 14-TSSOP
MCP795W22T-I/ST FAQ
1.How can I place an order for MCP795W22T-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP795W22T-I/ST on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MCP795W22T-I/ST reliable?
The price and inventory of MCP795W22T-I/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MCP795W22T-I/ST is usually 5 days.
3.What payment methods are accepted for MCP795W22T-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP795W22T-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCP795W22T-I/ST?
MCP795W22T-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP795W22T-I/ST order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MCP795W22T-I/ST?
For technical support, including MCP795W22T-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP795W22T-I/ST requirements.
6.How does Aetrix verify that MCP795W22T-I/ST is sourced from the original manufacturer or authorized distributors?
All MCP795W22T-I/ST products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MCP795W22T-I/ST meets industry standards.
7.What is the process for return or replacement of MCP795W22T-I/ST?
All MCP795W22T-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with MCP795W22T-I/ST, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MCP795W22T-I/ST part is unused and in its original packaging.
Return procedure for MCP795W22T-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MCP795W22T-I/ST Tags
-
MCP7940N-I/SN
Microchip Technology
-
MCP7940MT-I/MNY
Microchip Technology
-
PCF85063ATL/1,118
NXP USA Inc.
-
MCP7940NT-I/SN
Microchip Technology
-
MCP7940NT-I/MS
Microchip Technology
-
MCP7940N-I/MS
Microchip Technology
-
PCF85063AT/AY
NXP USA Inc.
-
PCF85063TP/1Z
NXP Semiconductors
-
PCF85063ATT/AJ
NXP USA Inc.
-
MCP7940NT-E/SN
Microchip Technology
-
MCP7940NT-I/MNY
Microchip Technology
-
MCP79400T-I/SN
Microchip Technology
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